conflicting advice... about audio... on the internet?????
Say it isn't so!!
OK, with one or two exceptions, there are very few "right" answers. Music production is part art, part science, and the phrase that I hear most often from my mentors is "it depends".
It would take a book - and I am way too lazy to type that much - to explain concert hall acoustics, and if you are trying to mix a concert hall-ish track you really do need to understand what goes on physically in a real hall.
In this case, strange though it may seem, you can manipulate the apparent position of a track by manipulating several different factors, including reverb density, reverb length, pre-delay level, pre-delay time, etc. They all interact, and depending on the track you can get great results by tweaking only one (which one???) but sometimes you'll have to tweak them all. "It Depends"
Here is one of the few instances where there is a "rule"... small critical listening spaces have a tendency to be non-reverberant. You can build a space that is large enough to be statistically reverberant, but most of us don't have that kind of room or cash.
Why do I mention this? In your monitoring space you not only have to deal with what should be happening in your imaginary space (the one you are trying to create) but also have to deal with what is really happening in your monitoring space. And the two will have conflicts. I think (pure speculation) this is one of the reasons why you will find more advice about tweaking early reflections or pre-delay in the popular press. I could be wrong about that<G>!
Just for grins, the only topic that I am aware of that has a single, correct answer (although you will find the contrary answer online) is safety grounds. NEVER defeat the safety ground!!!!
Other than that, well, audio production is what it is, and the art is at least as important as the science, if not maybe a little more so.